varaverk: monitor overhaul — CPU/memory/network/streams cards; scheduler polish

Monitor tab:
- CPU card: per-core bars (freq-colored), overall usage bar, rolling history chart
- Memory card: breakdown by system/VM/ZFS/Docker/free with progress bars
- Network card: LAN + ext + Tailscale IP display, live RX/TX chart with auto-scale
- Streams card: Emby/Jellyfin/Plex sessions with playback bar and server badges
- GPU card: adds power draw, encode%, decode% meters
- Transcode card: ramdisk vs SSD location pill, session count, flip history
- Canvas chart helpers: vvDrawChart, vvDrawNetChart, vvMeter, vvFmtBps, vvFmtGib

api/monitor.php: adds cpu, mem, net to response payload

Plugin/usr/local/emhttp/plugins/varaverk/api/run.php

@@ -19,8 +19,7 @@ $logFile = vv_job_log_path($id);
 $logDir  = dirname($logFile);
 if (!is_dir($logDir)) mkdir($logDir, 0755, true);
 
-// Stamp the log so the panel shows when the run started
-file_put_contents($logFile, date('[Y-m-d H:i:s]') . " Manual run started\n", FILE_APPEND);
+file_put_contents($logFile, "\n── " . date('Y-m-d H:i:s') . " ──────────────────────\n", FILE_APPEND);
 
 $flags = vv_job_flags($id);
 exec('nohup bash ' . escapeshellarg($script) . ($flags ? " $flags" : '') . ' >> ' . escapeshellarg($logFile) . ' 2>&1 </dev/null &');